The prior art, such as Swedish Patent Nos. 504,011; 515,543; and 501,719 show examples of dewatering devices, which comprise liquid permeable press rolls with a nip formed between them for dewatering a material suspension of wood fiber pulp. The pulp suspension is supplied to a portion of the device, which is under pressure and surrounded by a casing, and the dewatered pulp egresses through the nip. The pulp suspension usually is supplied either from above or from below, as can be seen from these references. The width of the outlet gap can vary, depending on the properties of the suspension which can be different along the length of the roll, and thus the roll can be angled in relation to the bearing housing. It may also be necessary to adjust the nip, i.e. to move at least one roll towards or away from the other roll, and during this movement the roll can be slightly angled. The pulp suspension is aggressive, and if it leaks into the bearings, the bearings will be destroyed. The sealing against the bearings, therefore, is of vital importance and an essential risk factor for the accessibility of the device.
Present dewatering devices use as sealing between the bearing housing and the axle stuffing boxes and V-ring sealings (of rubber). They do not withstand, however, the aggressive environment of the pulp suspension and are destroyed and lose their sealing capacity.
One object of the present invention is to provide a sealing device for sealing between a bearing housing and the axle journal of a roll, the two bearing housings of which for the axle journal bearings are movable in the direction across the axle, where this sealing device shall have a long service life even in an aggressive environment, and which allows the axle to be slightly angled in a plane during the movement, and in which the sealing can also take up a certain degree of axial movement. A more specific object of the present invention is, by providing improved sealing devices, to increase the operational reliability of a device for dewatering and/or washing material suspensions, comprising at least one cylindrical rotary roll, which is surrounded by a casing with an inlet for the material suspension, and which against an element forms a gap for the egress of pulp, and the axle journals of the roll are mounted in bearings supported by bearing housings movable in the direction across the axle.